Ability to update shared Gists

[officedev]

Ability to update shared Gists

[saunders77]

seems like this is very cuttable
triage-postponable

[Zlatkovsky]

• If shared as a gist, probably ok to just update in place. (Maybe add a "duplicate" functioanilty for the odd case)
• If import an existing gist (via URL):
  • if it's your gist (check), then resume using it as is and updating as is
  • if it's someone else's, clear out the "gist" field and assume it's new.
• [Optional: re-parenting option to re-specify (and view) current gist ID]. Maybe under snippet profile, should have option to input a different gist id if you please.